Built-in self-test (BIST) circuitry and systems are used for automated testing of target circuits during product manufacturing and/or during circuit operation, such as on power up. Many BIST circuits include a controller that produces test conditions for one or more target circuits, and receives or analyzes responses to identify any faulted target circuitry. The target circuits may be electronic memory, and the self-test can include writing of the desired data pattern to an embedded memory, and then addressing the memory to retrieve and compare the stored data to the expected data. In certain product applications, BIST circuits need to complete testing in a predetermined time, during which circuit power may be limited. Also, BIST circuits can occupy significant circuit area, particularly where a BIST controller is provided for each of a number of target circuits.